It seems the expression evaluator most often doesn't work. It always tries to import something that it doesn't get. I tried the Scala compiler itself. Breakpoint inside GlobalPhase.run.

Try the simplest expression: `this`. Here's what I get:

 this

 Compilation failed
object mutable is not a member of package collection

It seems the evaluator's classpath is never complete. I personally couldn't find a single project where it works.